Adaptive Z-Offset Measurement (Patreon)

Hey everyone! Sorry things have been a bit quiet from my side this past week. I was still recovering from COVID, and trust me—running a loud CPAP printer right next to you with a pounding headache isn't fun.

So I was focusing on some enhancements to the THEOS firmware. Over the past few weeks, I've noticed that the BD sensor occasionally produces false-positive readings during the second homing cycle. Although these errors seemed sporadic, there was actually a consistent pattern whenever they occurred. After some digging, I suspected the issue might stem from an incompatibility between my modified second homing routine and the sensor's internal workflow.

I reached out to Markniu, and together we identified the root cause. The solution involves making some architectural changes to how homing is handled overall. It’s a bit more development effort, but the payoff will be huge—we'll be able to measure Z-distance in real-time.

In the video attached, you can see a quick-and-dirty implementation of Adaptive Z-Offset. The results were pretty impressive: out of 10 test patterns, 7 had absolutely perfect first layers. The remaining 3 had minor scratches on the underside, each smaller than a 1x1 cm patch—annoying, sure, but definitely not a dealbreaker.

This week, I'll be focusing on implementing the necessary changes for the Z-Offset feature. Additionally, there have been several bug reports on Discord and here on Patreon. I'll reproduce and address these issues, aiming to roll out a fresh update by the end of the week.